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BAB Racer to Cafe Racer

After many let downs on trying to buy a bike that met the criteria of the "Build A Bike" race challenge, and furthermore, that it could be prepared/repaired within the $600 budget, I came across a 1985 ZX600R Ninja that was 99% intact and was running recently, but was believed to have carburetor problems.

When Wendy and I turned up to view the bike, the guy had started taking it apart so he could fix the carbs. I checked the bike out, it turned over OK brakes were OK but sticking slightly, tires were shot. The front forks were nearly solid and would only depress about 1 inch, I decided this was due to the fork anti-dive units having seized up, which would be similar to winding the compression damping in full on a modern bike. Other than the bike looking very grim with a poor black rattle can paint job and an abundance of black over-spray everywhere, it seemed like a good candidate.

We agreed on $400, loaded it up, grabbed the spare carbs and some miscellaneous spares along with the bodywork and headed home.

Now to find out what we have and what needs doing.. I removed the carbs ready for examination and cleaning, then removed the plugs to give me an idea how the bike was running prior to it's carburetor issues. The plugs revealed that the engine was not burning any oil and was running fairly rich...good start!

I cranked the engine on the stater long enough to get oil around the engine and also put a small amount of engine oil in each cylinder to lubricate the piston/rings and cylinder prior to the compression check. The compression check revealed a compression of approx 10.5:1 on all 4 cylinders, slightly down on the stock 11:1. Given the bike hadn't been running for some time and the oil distribution in the cylinders wouldn't be very good until the engine was running, I was very happy with these figures.

The next job was to investigate the front fork issues; I removed the brake lines so that I could take the small brake activated pistons on top of the anti-dive units off, as you can see in the photos, they were in very poor condition. I placed the anti-dive units in WD40 to help free them up prior to dis-assembly.

It's a good base they were a very competent bike in their day, I had the british version GPZ600R and loved it...it has 16"wheels front and rear which severely limits tire choice, but I intend to rework the forks to get better handling and swap the rear shock out for a gixxer one if it fits...just happen to have two of them laying around the forks are a challenge, but I'm up for it

I have started work on the carburetors now; the carbs appear to have been jetted up at some point, so I need to get the stock information to work from, but in the meantime, it's completely strip and examine every part for damage, corrosion, blockages, etc. and checking the diaphragms for splits or holes.

I have cleaned one carb thoroughly and it is in good shape, 3 more to go! However, the jets look to have been put in with one of those hammerscrewdriver things by the look of them

We will most likely have to rejet as we won't be running an air box (as that is missing) and I will be making a new exhaust for the bike to help with performance... I will post up photos of the exhaust build, but that will be several weeks away yet.

I am encouraged by the bikes overall condition, so far we will have to buy jets and spark plugs...plugs are OK, but it would be prudent to replace them..